The asteroid strike that wiped out the dinosaurs occurred during the northern spring according to a recent study. Scientists from The University of Manchester and other institutions across the world have published a ground-breaking study in the journal Scientific Reports today that provides fresh light on the timing of the dinosaur-killing asteroid strike that happened 66 million years ago.
The study title ‘Seasonal calibration of the end-Cretaceous Chicxulub Impact Event” new evidence that aids in our understanding of the significance of timing for the event that brought about the extinction of dinosaurs—as well as the extinction of 75 percent of life on Earth. According to the study, the event occurred paradoxically during the northern spring, a season linked with the rebirth of life.
Researchers led by Ph.D. student Robert DePalma of the University of Manchester examined the Tanis research site in North Dakota, USA, which is one of the most highly detailed Cretaceous-Paleogene (KPg) boundary sites in the world, in order to better understand the internal workings of the extinction event.
“This project has been a tremendous endeavor, but it has been well worth it,” DePalma said. “We have been collecting and processing data for many years, and now we have convincing evidence that not only affects our perception of the KPg event but also may help us better prepare for future biological and environmental threats.”
“While extinction may signify the end of a dynasty, we must remember that our own species may not have developed if it had not been for the impact and timing of circumstances that brought the dinosaurs to their end.”
Previous studies have conclusively shown the disastrous Chicxulub asteroid impact that struck the Yucatan Peninsula 66 million years ago, resulting in the destruction of the whole region.
When the impact occurred, it precipitated the most well-known extinction catastrophe in Earth’s history, causing global biomes to change radically in ways that are closely related to our present global ecological disaster. What remains a mystery is the specifics of what transpired in the time period between the impact and the ensuing collapse of planetary ecosystems.
DePalma’s team previously documented that the new site, which has been named Tanis, contains the only impact-caused vertebrate mass-death assemblage at the KPg boundary, using multiple lines of evidence including radiometric dating, stratigraphy, fossilized remains of biological marker species, and a distinctive capping layer of iridium-rich clay.
A definitive date was established for the site, which was toward the end of the Cretaceous period and during the first few hours after the Chicxulub impact (DePalma et al., 2019).
It was discovered in the same research that a tremendous rush of water, connected with major tremors generated by the impact, was responsible for the swiftly formed sediments that were utilized in this study to lock in the evidence. It has provided an unparalleled chance to clarify information about the KPg event as well as the biota that perished as a result of it and the habitat in which they resided because of the tightly packed mass of plants, animals, trees, and impact ejecta.
Seasonal variations in numerous biological activities, including reproduction, feeding tactics, host-parasite interactions, seasonal dormancy, and breeding patterns are all influenced by the time of year. As a result, it should come as no surprise that the time of year a global-scale danger occurs may have a significant influence on how severely it damages human lives. Therefore, the seasonal date of the Chicxulub impact has been a significant topic in the account of extinction during end-Cretaceous times.
Thanks to a mix of conventional and cutting-edge procedures, the multidisciplinary team has been able to put together data that has permitted the determination of the season (northern spring) in which the Chicxulub impact event occurred. “The work at Tanis has been enlightening and very fun,” said Robert DePalma, the study’s principal author. With such a strong link to prehistory, our whole staff is provided with a chance of a lifetime”.
The researchers examined growth lines preserved in the fossil bones of fish that perished as a result of the strong impact-triggered event that occurred at the Tanis site. These growth lines serve as a unique record of the fishes’ lives, and the bony development pattern of the fishes allowed the researchers to determine the season in which they died based on the fishes’ life histories.
The development lines have a distinct structure and pattern that is comparable to a barcode, and this provides proof that all of the ancient fish studied perished during the Spring-Summer growth season, according to the researchers. Independent support of this was obtained by isotopic analysis of the growth lines in the fish bones, which revealed an annual seasonal oscillation that likewise ceased at the Spring-Summer growth period.
According to the researchers, the finding offers long-awaited information that contributes to the confirmation of earlier studies on the time of the KPg mass extinction. It is critical to reconstruct the reasons for post-impact biotic response and extinction patterns, and the many lines of evidence uncovered in this work serve as a starting point.
Scientists and natural historians will find this information useful, but it will also be useful to anyone living in the modern world. The fossil record holds the key to understanding the reaction of life to global-scale threats, whether they occurred in the past, are now occurring, or will occur in the future. As Prof. Phil Manning, a co-author on the research put it, “The hindsight that the fossil record affords may provide vital data, which we can use now in order to better prepare ourselves for the future.”
